libiio  0.26
Library for interfacing with IIO devices
ad9371-iiostream.c

This example libiio program is meant to exercise the features of IIO functionality on the AD9371.

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* libiio - AD9371 IIO streaming example
*
* Copyright (C) 2014 IABG mbH
* Author: Michael Feilen <feilen_at_iabg.de>
* Copyright (C) 2017 Analog Devices Inc.
**/
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <signal.h>
#include <stdio.h>
#include <iio.h>
/* helper macros */
#define MHZ(x) ((long long)(x*1000000.0 + .5))
#define GHZ(x) ((long long)(x*1000000000.0 + .5))
#define IIO_ENSURE(expr) { \
if (!(expr)) { \
(void) fprintf(stderr, "assertion failed (%s:%d)\n", __FILE__, __LINE__); \
(void) abort(); \
} \
}
/* RX is input, TX is output */
enum iodev { RX, TX };
/* common RX and TX streaming params */
struct stream_cfg {
long long lo_hz; // Local oscillator frequency in Hz
};
/* static scratch mem for strings */
static char tmpstr[64];
/* IIO structs required for streaming */
static struct iio_context *ctx = NULL;
static struct iio_channel *rx0_i = NULL;
static struct iio_channel *rx0_q = NULL;
static struct iio_channel *tx0_i = NULL;
static struct iio_channel *tx0_q = NULL;
static struct iio_buffer *rxbuf = NULL;
static struct iio_buffer *txbuf = NULL;
static bool stop;
/* cleanup and exit */
static void shutdown(void)
{
printf("* Destroying buffers\n");
if (rxbuf) { iio_buffer_destroy(rxbuf); }
if (txbuf) { iio_buffer_destroy(txbuf); }
printf("* Disabling streaming channels\n");
if (rx0_i) { iio_channel_disable(rx0_i); }
if (rx0_q) { iio_channel_disable(rx0_q); }
if (tx0_i) { iio_channel_disable(tx0_i); }
if (tx0_q) { iio_channel_disable(tx0_q); }
printf("* Destroying context\n");
if (ctx) { iio_context_destroy(ctx); }
exit(0);
}
static void handle_sig(int sig)
{
printf("Waiting for process to finish... Got signal %d\n", sig);
stop = true;
}
/* check return value of attr_write function */
static void errchk(int v, const char* what) {
if (v < 0) { fprintf(stderr, "Error %d writing to channel \"%s\"\nvalue may not be supported.\n", v, what); shutdown(); }
}
/* write attribute: long long int */
static void wr_ch_lli(struct iio_channel *chn, const char* what, long long val)
{
errchk(iio_channel_attr_write_longlong(chn, what, val), what);
}
/* write attribute: long long int */
static long long rd_ch_lli(struct iio_channel *chn, const char* what)
{
long long val;
errchk(iio_channel_attr_read_longlong(chn, what, &val), what);
printf("\t %s: %lld\n", what, val);
return val;
}
#if 0
/* write attribute: string */
static void wr_ch_str(struct iio_channel *chn, const char* what, const char* str)
{
errchk(iio_channel_attr_write(chn, what, str), what);
}
#endif
/* helper function generating channel names */
static char* get_ch_name_mod(const char* type, int id, char modify)
{
snprintf(tmpstr, sizeof(tmpstr), "%s%d_%c", type, id, modify);
return tmpstr;
}
/* helper function generating channel names */
static char* get_ch_name(const char* type, int id)
{
snprintf(tmpstr, sizeof(tmpstr), "%s%d", type, id);
return tmpstr;
}
/* returns ad9371 phy device */
static struct iio_device* get_ad9371_phy(void)
{
struct iio_device *dev = iio_context_find_device(ctx, "ad9371-phy");
IIO_ENSURE(dev && "No ad9371-phy found");
return dev;
}
/* finds AD9371 streaming IIO devices */
static bool get_ad9371_stream_dev(enum iodev d, struct iio_device **dev)
{
switch (d) {
case TX: *dev = iio_context_find_device(ctx, "axi-ad9371-tx-hpc"); return *dev != NULL;
case RX: *dev = iio_context_find_device(ctx, "axi-ad9371-rx-hpc"); return *dev != NULL;
default: IIO_ENSURE(0); return false;
}
}
/* finds AD9371 streaming IIO channels */
static bool get_ad9371_stream_ch(enum iodev d, struct iio_device *dev, int chid, char modify, struct iio_channel **chn)
{
*chn = iio_device_find_channel(dev, modify ? get_ch_name_mod("voltage", chid, modify) : get_ch_name("voltage", chid), d == TX);
if (!*chn)
*chn = iio_device_find_channel(dev, modify ? get_ch_name_mod("voltage", chid, modify) : get_ch_name("voltage", chid), d == TX);
return *chn != NULL;
}
/* finds AD9371 phy IIO configuration channel with id chid */
static bool get_phy_chan(enum iodev d, int chid, struct iio_channel **chn)
{
switch (d) {
case RX: *chn = iio_device_find_channel(get_ad9371_phy(), get_ch_name("voltage", chid), false); return *chn != NULL;
case TX: *chn = iio_device_find_channel(get_ad9371_phy(), get_ch_name("voltage", chid), true); return *chn != NULL;
default: IIO_ENSURE(0); return false;
}
}
/* finds AD9371 local oscillator IIO configuration channels */
static bool get_lo_chan(enum iodev d, struct iio_channel **chn)
{
switch (d) {
// LO chan is always output, i.e. true
case RX: *chn = iio_device_find_channel(get_ad9371_phy(), get_ch_name("altvoltage", 0), true); return *chn != NULL;
case TX: *chn = iio_device_find_channel(get_ad9371_phy(), get_ch_name("altvoltage", 1), true); return *chn != NULL;
default: IIO_ENSURE(0); return false;
}
}
/* applies streaming configuration through IIO */
bool cfg_ad9371_streaming_ch(struct stream_cfg *cfg, enum iodev type, int chid)
{
struct iio_channel *chn = NULL;
// Configure phy and lo channels
printf("* Acquiring AD9371 phy %s channel %d\n", type == TX ? "TX" : "RX", chid);
if (!get_phy_chan(type, chid, &chn)) { return false; }
rd_ch_lli(chn, "rf_bandwidth");
rd_ch_lli(chn, "sampling_frequency");
// Configure LO channel
printf("* Acquiring AD9371 %s lo channel\n", type == TX ? "TX" : "RX");
if (!get_lo_chan(type, &chn)) { return false; }
wr_ch_lli(chn, type == TX ? "TX_LO_frequency" : "RX_LO_frequency" , cfg->lo_hz);
return true;
}
/* simple configuration and streaming */
int main (__notused int argc, __notused char **argv)
{
// Streaming devices
struct iio_device *tx;
struct iio_device *rx;
// RX and TX sample counters
size_t nrx = 0;
size_t ntx = 0;
// Stream configurations
struct stream_cfg rxcfg;
struct stream_cfg txcfg;
// Listen to ctrl+c and IIO_ENSURE
signal(SIGINT, handle_sig);
// RX stream config
rxcfg.lo_hz = GHZ(2.5); // 2.5 GHz rf frequency
// TX stream config
txcfg.lo_hz = GHZ(2.5); // 2.5 GHz rf frequency
printf("* Acquiring IIO context\n");
IIO_ENSURE((ctx = iio_create_default_context()) && "No context");
IIO_ENSURE(iio_context_get_devices_count(ctx) > 0 && "No devices");
printf("* Acquiring AD9371 streaming devices\n");
IIO_ENSURE(get_ad9371_stream_dev(TX, &tx) && "No tx dev found");
IIO_ENSURE(get_ad9371_stream_dev(RX, &rx) && "No rx dev found");
printf("* Configuring AD9371 for streaming\n");
IIO_ENSURE(cfg_ad9371_streaming_ch(&rxcfg, RX, 0) && "RX port 0 not found");
IIO_ENSURE(cfg_ad9371_streaming_ch(&txcfg, TX, 0) && "TX port 0 not found");
printf("* Initializing AD9371 IIO streaming channels\n");
IIO_ENSURE(get_ad9371_stream_ch(RX, rx, 0, 'i', &rx0_i) && "RX chan i not found");
IIO_ENSURE(get_ad9371_stream_ch(RX, rx, 0, 'q', &rx0_q) && "RX chan q not found");
IIO_ENSURE(get_ad9371_stream_ch(TX, tx, 0, 0, &tx0_i) && "TX chan i not found");
IIO_ENSURE(get_ad9371_stream_ch(TX, tx, 1, 0, &tx0_q) && "TX chan q not found");
printf("* Enabling IIO streaming channels\n");
printf("* Creating non-cyclic IIO buffers with 1 MiS\n");
rxbuf = iio_device_create_buffer(rx, 1024*1024, false);
if (!rxbuf) {
perror("Could not create RX buffer");
shutdown();
}
txbuf = iio_device_create_buffer(tx, 1024*1024, false);
if (!txbuf) {
perror("Could not create TX buffer");
shutdown();
}
printf("* Starting IO streaming (press CTRL+C to cancel)\n");
while (!stop)
{
ssize_t nbytes_rx, nbytes_tx;
char *p_dat, *p_end;
ptrdiff_t p_inc;
// Schedule TX buffer
nbytes_tx = iio_buffer_push(txbuf);
if (nbytes_tx < 0) { printf("Error pushing buf %d\n", (int) nbytes_tx); shutdown(); }
// Refill RX buffer
nbytes_rx = iio_buffer_refill(rxbuf);
if (nbytes_rx < 0) { printf("Error refilling buf %d\n",(int) nbytes_rx); shutdown(); }
// READ: Get pointers to RX buf and read IQ from RX buf port 0
p_inc = iio_buffer_step(rxbuf);
p_end = iio_buffer_end(rxbuf);
for (p_dat = iio_buffer_first(rxbuf, rx0_i); p_dat < p_end; p_dat += p_inc) {
// Example: swap I and Q
const int16_t i = ((int16_t*)p_dat)[0]; // Real (I)
const int16_t q = ((int16_t*)p_dat)[1]; // Imag (Q)
((int16_t*)p_dat)[0] = q;
((int16_t*)p_dat)[1] = i;
}
// WRITE: Get pointers to TX buf and write IQ to TX buf port 0
p_inc = iio_buffer_step(txbuf);
p_end = iio_buffer_end(txbuf);
for (p_dat = iio_buffer_first(txbuf, tx0_i); p_dat < p_end; p_dat += p_inc) {
// Example: fill with zeros
// 14-bit sample needs to be MSB aligned so shift by 2
// https://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/software/basic_iq_datafiles#binary_format
((int16_t*)p_dat)[0] = 0 << 2; // Real (I)
((int16_t*)p_dat)[1] = 0 << 2; // Imag (Q)
}
// Sample counter increment and status output
nrx += nbytes_rx / iio_device_get_sample_size(rx);
ntx += nbytes_tx / iio_device_get_sample_size(tx);
printf("\tRX %8.2f MSmp, TX %8.2f MSmp\n", nrx/1e6, ntx/1e6);
}
shutdown();
return 0;
}
void * iio_buffer_first(const struct iio_buffer *buffer, const struct iio_channel *chn)
Find the first sample of a channel in a buffer.
Definition: buffer.c:250
ptrdiff_t iio_buffer_step(const struct iio_buffer *buffer)
Get the step size between two samples of one channel.
Definition: buffer.c:288
void * iio_buffer_end(const struct iio_buffer *buffer)
Get the address that follows the last sample in a buffer.
Definition: buffer.c:293
void iio_buffer_destroy(struct iio_buffer *buffer)
Destroy the given buffer.
Definition: buffer.c:104
ssize_t iio_buffer_refill(struct iio_buffer *buffer)
Fetch more samples from the hardware.
Definition: buffer.c:123
ssize_t iio_buffer_push(struct iio_buffer *buffer)
Send the samples to the hardware.
Definition: buffer.c:147
struct iio_buffer * iio_device_create_buffer(const struct iio_device *dev, size_t samples_count, bool cyclic)
Create an input or output buffer associated to the given device.
Definition: buffer.c:26
int iio_channel_attr_read_longlong(const struct iio_channel *chn, const char *attr, long long *val)
Read the content of the given channel-specific attribute.
Definition: channel.c:689
void iio_channel_enable(struct iio_channel *chn)
Enable the given channel.
Definition: channel.c:452
ssize_t iio_channel_attr_write(const struct iio_channel *chn, const char *attr, const char *src)
Set the value of the given channel-specific attribute.
Definition: channel.c:419
int iio_channel_attr_write_longlong(const struct iio_channel *chn, const char *attr, long long val)
Set the value of the given channel-specific attribute.
Definition: channel.c:729
void iio_channel_disable(struct iio_channel *chn)
Disable the given channel.
Definition: channel.c:458
struct iio_context * iio_create_default_context(void)
Create a context from local or remote IIO devices.
Definition: context.c:415
void iio_context_destroy(struct iio_context *ctx)
Destroy the given context.
Definition: context.c:258
unsigned int iio_context_get_devices_count(const struct iio_context *ctx)
Enumerate the devices found in the given context.
Definition: context.c:280
struct iio_device * iio_context_find_device(const struct iio_context *ctx, const char *name)
Try to find a device structure by its ID, label or name.
Definition: context.c:294
ssize_t iio_device_get_sample_size(const struct iio_device *dev)
Get the current sample size.
Definition: device.c:483
struct iio_channel * iio_device_find_channel(const struct iio_device *dev, const char *name, bool output)
Try to find a channel structure by its name of ID.
Definition: device.c:157
Public interface.
An input or output buffer, used to read or write samples.
Represents an input or output channel of a device.
Contains the representation of an IIO context.
Represents a device in the IIO context.